I have 13 series and they are all on both network and local computer. A lot of time when MP starts up, it just recognize the ones in local computer but not those stored in network, after turn on and off MP few times all series show up again. So I tried both the stable version and this version but the problem still exists.
Might be a problem with your network or computer. I use to have troubles with my network card not initializing fast enough after resume from standby. Be sure you have the latest stable drivers for your NIC and also your M/B Chipset. Also good idea not to power down the NIC when entering standby, using a static IP instead of using DHCP.
I have the latest and stable driver for my NIC and chipset, but not sure how not to power down NIC. But I don't think it's the problem because I am also using Moving Pictures and it doesn't have problem like that